Buffing and polishing compositions and method of preparation



Patent v. 14, 1950 trap STATES PATEN FEE BUFFING AND POLISHING COMPOSITIONS AND METHOD OF PREPARATION Allan E. Chester, Highland Park, Ill., assignor t Poor & Company, Chicago, 111., a corporation of Delaware No Drawing. Application August 27, 1948, Serial No. 46,563

Claims. 1

-' thereof.

In bufling and polishing brass, copper, nickel and other base metals, usually for finishing or preparatory to plating, two classes of abrasives have been employed, namely, natural abrasives such as carborundum, silica and quartz, and synthetic abrasives such as aluminum oxides, silicon carbides and precipitated ferric oxide, chromic oxide or other oxides. It is customary to employ binders such as waxes, tallows, stearic acid together with the abrasive in the buillng and polishing compositions. The bufilng and polishing compositions are usually prepared in the form of a cake which can be applied to a bufling wheel and transferred to it prior to the polishing or bufling operation.

In preparing such builing and polishing compositions, it has always been considered necessary heretofore to have the abrasive in an extremely fine, uniform particle size.

One of the objects of the present invention is to provide bufllng and polishing compositions containing as an abrasive material a substance which has never been used before for this purpose and which is highly effective in such bufling and polishing operations.

Another object of the invention is to provide a new and improved bufiing and polishing composition in which the active polishing agent exists in the composition in a relatively large range of particle sizes.

Still a, further object of the invention is to provide a new and improved method for preparing bufling and polishing compositions. Other objects will appear hereinafter.

In accordance with the present invention it has been found that new and improved results are obtained in bufiing and polishing operations by employing as the abrasive tailings,.--from a conglomerate copper ore of the type found in Houghton, Keweenaw, and Ontonagon counties of northern Michigan, United States of America.

The term tailings has a recognized meaning in the art pertaining to the recovery of copper from its ores and refers to the residue which is left after the ore has been treated to extract practically all of the copper, leaving iron and silicon as the principal constituents, together with alkali metals combined in the form of salts or complex oxides and smaller amounts of other metals.

In ordinary practice, the copper ore is mined, crushed, and extracted by procedures which include leaching, electrolysis, flotation and smelting. The ore is often treated, retreated and ground and the residue or tailings are finally discarded, usually by pumping them into a lake or a body of water. These tailings' have found no large scale use up to the present time.

A typical analysis of such tailings taken from the conglomerate tailings of the Calumet 8r Hecla Company, near Calumet, Michigan, showed a hardness of 7.0to'7.3 on the Moh scale. An

analysis for size indicated the following:

Retained on Screen Mesh Weight (Openings per Per Cent Sq. In.)

5 40 7. 5 21. 5 34 8. 5 200 16 more than 200 7. 5

These tailings contain about4% moisture. A spectro-chemical analysis showed the presence of the following metals:

Iron, Silicon .1'.' Principal Constituents Potassium 2 to 20% Sodium 1 to 10% Copper 0.05 to 0.5% Chromium 0.01 to 0.1% Aluminum 0.01 to 0.1% Calcium 0.01 to 0.1% Titanium 0.001 to 0.01% Vanadium 0.001 to 0.01% Magnesium 0.001 to 0.01% Tin, Silver, Nickel, Cobalt, Lead traces 1 1 Less than 0.001% is present.

It is of interest to note that iron and silicon are the principal constituents and therefore the chief components of the substance which has been found to have unusual effectiveness as an abrasive in the practice of this invention. Heretofore it has been thought that iron could not be used in polishing chromium because it would cause discoloration. In the practice of the present invention, how'ever, excellent results have been obtained in polishing chromium despite the presence of the iron.

A novel method is used in accordance with the present invention in order to incorporate the previously described tailings into a suitable bufllng or polishing composition. This method is also applicable to the preparation of other t pes of bufilng and polishing compositions with other types of abrasives. The method may be described briefly as follows. N

The conglomerated tailings in any suitable quantity, say in 40 pound to 100 pound batches, are wet milled with water, a gel-forming colloid, e. g., bentonite, and an electrolyte in order to make a slip or aqueous slurry similar in appearance to the slips or slurries which are made with vitreous enamel frits prior to applying and firing enamel. The slurry or slip is ground in a ball mill of the type used in grinding vitreous enamels until the particle sizes are reduced to at least of the particle sizes in the tailings employed as the starting materials.

The preferred method of procedure is to ball mill the tailings with to 3% by weightof bentonite, 96% to by weight of sodium nitrite, magnesium sulfate or other electrolyte, and 35% to 45% water. This forms a colloidal slip which suspends the particles and facilitates further grinding in the ball mill. The amount of the grinding may be controlled depending upon the purpose for which the buffing composition is to be employed, for example, if the bufdng composition is to be employed on die castings, the maximum particle size may be somewhat greater than in other applications, and the preferred maximum particle size in such case is 150 mesh. Where the bufling composition is to be employed for polishing aluminum, the preferred maximum particle size is 200 mesh. For a typical composition of the type just described 150 mesh maximum particle size can be obtained in about six hours ball milling and 200 mesh maximum particle size can be obtained in about eight hours ball milling. The product after ball milling has a multi-particle size similar to that of the original product but reduced by a ratio of around 5:1 to 8:1, depending upon the extent of the ball milling.

After the colloidal slip has been ball milled as previously described, it is run through a Roto- Spray to expel particles of any desired size, and it is then passed over a magnetic separator to remove any magnetic particles. After passing over the magnetic separator, it goes to settling tanks and is treated with agents which are known to cause separation of the water, such as, for example, tetrasodiumpyrophosphate and many other polyphosphates. These agents may be described as defiocculating and degelling agents. The excess water is removed by decantation and the resultant product is dried in the form of cakes. The cakes are broken up in a hammer mill and formulated into the final buffing composition. A typical final bufling composition may be prepared as follows:

These ingredients melted together and molded form a suitable bar for bufllng brass, aluminum, copper and other metals. The specified quantities in grams are sufiicient to produce one bar.

In the foregoing composition the standard petrolatum No. 3292 has the following physical properties:

iii

Specific gravity .880.85 Flash point 495 F. Fire point 555 F. Viscosity 210 F 95-120 S. U. S. Color 6-? Melting point 150-155 F.

Typical Hydrofol acids and glycerides which may be employed for the purpose of the invention have the following compositions:

1 Free fatty acid is olcic acid.

The crude scale wax has the following composition:

Melting point F 122432 Viscosity (210 F.) (seconds) 40-45 Flash point (minimum) F. 400 Oil content (maximum) "percent" 20 (minimum) percent 2 Weight (pounds per gallon) 6.89

The name Hydrofol is the trade name of the Werner G. Smith Company, Cleveland, Ohio, for hydrogenated fish oils and acids as described above.

From the foregoing illustration, it will be seen that the final abrasive composition is composed principally of the abrasive material and contains minor proportions of a gel-forming colloid and a binder. The binder in this case consists of the stearic acid, hydrogenated fish oil, waxes and glycerides. The composition preferably contains about to of the abrasive material, about to 1% of bentom'te and the remainder a wax type binder.

It will be understood that abrasives prepared in the manner previously described may be incorporated with any bufiing composition. Such compositions may contain as much as 75% of the abrasive and the remainder being a. paraffin wax, stearic acid or other type of amorphous binder. It is also desirable to incorporate with the bufling composition as much as A% to 2% of a grease-soluble wetting agent, for example, the wetting agent sold under the name Igepal.

The terms buffing and polishing" are used herein in their conventional sense as employed in the art. Polishing usually refers to a roughing out process while buffing refers to the final finishing.

The compositions of the invention have been extremely effective in the bufiing and polishing of various metals including chromium, aluminum and copper, even in the more diflicult types of bufling, such as die cast bufllng. The results obtained are surprising in view of the fact that the abrasive particles are of varying particle sizes, whereas the art has always attempted to reduce the abrasive particles to a uniform size. A further surprising result is the fact that the presence of iron in these particles does not mar or discolor chromium surfaces. The invention also provides a way of utilizing waste materials which heretofore have been of virtually no value and have presented a disposal problem. Another advantage of the invention is that the compositions herein described can be employed for bumng stainless steel or chromium plate without using aluminum oxide or chromic oxide.

The invention is hereby claimed as follows:

1. A bufling and polishing composition comprising a mass of binder material and comminuted abrasive material distributed therethrough, said abrasive material consisting essentially of multi-sized particles derived by grinding tailings of conglomerated copper ore.

2. A bufling and polishing composition comprising a mass of binder material and comminuted abrasive material distributed therethrough, said abrasive material consisting essentially of multi-sized particles derived by grinding tailings of conglomerated copper ore having a Moh scale hardness of at least 7.0.

3. A builing and polishing composition comprising a mass of binder material and comminuted abrasive material distributed therethrough, said abrasive material consisting essentially of multi-sized particles derived by grinding multi-sized abrasive particles of tailings of conglomerated copper ore of which at least 5% is retained on a 30 mesh screen and not more than 7.5% will pass through a 200 mesh screen until the particle size has been reduced 5 to 8 times.

4. A bufling and polishing composition comprising a mass of binder material and comminuted abrasive material distributed therethrough, said abrasive material consisting essentially of multi-sized particles derived by grinding multi-sized abrasive particles of which at least 5% is retained on a 30 mesh screen and not more than 7.5% will pass through a 200 mesh screen until the particle size has been reduced 5 to 8 times, said multi-sized particles consisting essentially of tailings from a. conglomerate copper ore found in northern Michigan having a Moh scale hardness of at least 7.0 and comprising principally iron and silicon with smaller amounts of alkali metals and less than 0.5% of copper and other metals.

5. A bumng and polishing composition, comprising a mass of binder material and a gel-forming colloid and a comminuted abrasive material distributed therethrough, said abrasive material being derived by grinding tailings from conglomerate copper ore of the type found in northern Michigan.

6. The process of preparing an abrasive which .6 comprises milling a multi-particle sized abrasive with a gel-forming colloid, an electrolyte and water to form a colloidal slip, ball milling said slip until the desired particle sizes in said abrasive are obtained, separating magnetic particles from the resultant composition, then treating the resultant product with a defloccuating and degeling agent to cause separation of the water therefrom, drying the product into cakes, breaking up the cakes and incorporating the produce derived from the broken up cakes with a binder material.

7. A process as claimed in claim 6 in which the abrasive particles are subjected to ball milling until the maximum particle size is 150 mesh.

. 8. A process as claimed in claim 6 in which a gel-forming colloid is incorporated with the abrasive material and the binder.

9. A buffing and polishing composition comprising essentially a minor proportion of a waxy binder and a major proportion of multi-sized particles derived by grinding tailings from a conglomerate copper ore found in northern Michigan having a Moh scale hardness of at least 7.0 and comprising principally iron and silicon with smaller amounts of alkali metals and less than 0.5% of copper and other metals.

10. A bufiing and polishing composition comprising essentially of to by weight of a comminuted abrasive material derived by grinding tailings from a conglomerate copper ore found in northern Michigan having a Moh scale hardness of at least 7.0 and comprising principally iron and silicon with smaller amounts of alkali metals and less than 0.5% of copper and other metals, and a wax-type binder.

ALLAN E. CHESTER..-

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

1. A BUFFING AND POLISHING COMPOSITION COMPRISING A MASS OF BINDER MATERIAL AND COMMINUTED ABRASIVE MATERIAL DISTRIBUTED THERETHROUGH, SAID ABRASIVE MATERIAL CONSISTING ESSENTIALLY OF MULTI-SIZED PARTICLES DERIVED BY GRINDING TAILINGS OF CONGLOMERATED COPPER ORE. 